Periodontal diseases such as dental caries are known as one of the most common chronic diseases in the field of dentistry. Dental caries, which is generally known as ‘tooth decay’, is a disease caused by gradual irreversible destruction of the hard tissues of the teeth (e.g., enamel, cementum and dentin). Periodontal diseases are induced mainly by bacterial film on the teeth. It is known that numerous microorganisms are present in the bacterial film on the teeth. It has been reported that the microorganisms in bacterial film on the teeth metabolize sugars to form an organic acid, thereby destructing the hard tissues of the teeth. Microorganisms in oral cavity form a biofilm, which is called as dental plaque. Toxic bacteria or toxins produced by them in the dental plaque invade the periodontal tissues to induce gingival inflammation, alveolar bone destruction and infection, which results in periodontal diseases. And also, an acid produced by such bacteria become a cause of dental caries.
As microorganisms inducing periodontal diseases and dental caries in oral cavity, are known Streptococcus mutans, Streptococcus sanguis, Actinobacillus viscosus, Lactobacillus acidophilus, etc. It is known that anaerobic microorganisms, among the microorganisms inducing periodontal diseases, produce inflammatory toxins; and therefore it is also important to inhibit or prevent the resulting immune responses. During the progress of inflammation in the periodontal disease, tissue destruction also occurs. When cell walls and tissues are damaged by the stimulus of bacterial endotoxins and other substances, membrane phospholipids in the cell wall are digested by an enzyme to release free arachidonic acid, thereby producing PGE2 and matrix metalloproteinases. Collagenase is one of the representative matrix metalloproteinases. Therefore, it is required in the art to develop an agent having both antimicrobial activity against periodontal disease-inducing bacteria and inhibitory effect against collagenase activity.
Korean Patent No. 10-0333445 has disclosed that ursodeoxycholic acid and/or chenodeoxycholic acid inhibit collagenase activity and thus are useful for an oral hygiene composition for preventing or treating periodontal disease. However, it has not disclosed whether or not ursodeoxycholic acid or chenodeoxycholic acid has an antimicrobial activity against periodontitis-inducing Streptococcus mutans, etc.